Enhanced Ethernet Switches

The new features are IGMP snooping, rate limiting, port security and Quality of Service (QoS) enhancements know as Diffserv, IEE802.1p and TOS. IGMP snooping is the ability of a switch to observe Internet Group Management Protocol (IGMP) traffic in order to learn IP Multicast group membership so as to restrict multicast transmissions to only those ports that have requested them. IGMP snooping is significant in large EtherNet/IP networks, says Bennet Levine, R&D manager at the vendor. “EtherNet/IP devices utilize multicast messages for their real-time data. But on a switch that doesn’t support IGMP snooping, these multicast messages will be handled like broadcast messages and potentially overwhelm some end-devices.” Rate limiting can be used to restrict certain devices from consuming too much network bandwidth. When port security is enabled, the switch will only pass traffic sent by specific devices. QoS enhancements allow specific ports or messages to have higher priority.